Chemetall Hoffman 5 Star Grit Blasted TAM Panel 3

It verifies that all elements of the process are functioning correctly. Any drastic change in the total process will be picked up and the danger of accepting a part with a dangerous flaw can be avoided. One half of the test piece is chrome plated with five crack centres evenly spaced down its length. The five crack centres are in the form of raised circular patterns and are arranged in order of magnitude.

The largest crack centre is approx. 6.4mm, the second largest 3.9mm, the third 2.3mm, the fourth 1.6mm and the smallest approx. 0.8mm. The largest is readily visible with low sensitivity materials.

The other half of the test piece is stainless steel, which has been oxide blasted to give a surface of medium roughness for testing background fluorescence when using high sensitivity penetrant systems. Regular processing of the 5 Star test panels at the beginning and end of a shift will help prove that a particular penetrant process is operating correctly. Knowing that faulty components cannot get through the system wrongly due to a major change in processing will increase confidence in the system.

An ultra-sensitivity penetrant should show all five cracks, a high sensitivity penetrant, should reveal four cracks, and on occasions, the fifth smallest crack. Similarly, a medium sensitivity penetrant should show the three largest cracks, and on occasions the fourth. Certain medium sensitivity penetrant will consistently show all five cracks on a given panel. However, it must be noted that the panel is not a sensitivity evaluation tool, it highlights problems by showing consistent numbers of cracks - the same number when processed each time.

Using the same panel to monitor both a high sensitivity and an ultra-high sensitivity system may produce false, misleading indications of the processing systems integrity, therefore it is important to maintain separate panels for each penetrant system being monitored.

Since on occasions, failure to detect the smallest cracks may arise from improper panel maintenance, two panels, one for daily use and a second (master) to verify the first, are usually required.